Indiana's Senate race has attracted about $4 million in outside spending, the highest of any congressional race this year, according to the Indianapolis Star.

State Treasurer Richard Mourdock received the bulk -- nearly 70 percent -- of those funds, for his challenge to incumbent Sen. Richard Lugar (R-Ind.) in next week's Republican primary, the Star found. The largest contributors on Mourdock's side included the anti-tax Club for Growth, which spent more than $1.7 million against Lugar, as well as the National Rifle Association and the Tea Party-aligned FreedomWorks for America. Lugar's biggest supporter was the pro-incumbent America Action Network.

Mourdock and Lugar are locked in a close primary battle that has taken a troubling turn for Lugar. The America Action Network recently canceled $200,000 in airtime, about a third of what it had planned to spend attacking Mourdock, and a recent poll showed Mourdock up five points.

10 more election stories from beyond the presidential field:

Tea Party Express, Local Tea Party Groups Split Over Sarah Steelman Endorsement [Springfield News-Leader]

Scott Brown Challenges 'Tracker' During Forum [The Eagle-Tribune]

Finance Chair For Dan Liljenquist Senate Campaign Resigns [Salt Lake Tribune]

Delaware Campaign Finance Bill Advances [Delaware News Journal]

Ron Paul Could Play Major Role In Deciding Minnesota's GOP Senate Nominee [Minnesota Public Radio]

Cuomo Fundraiser Nets $450,000 [Buffalo News]

Virginia Senate Race Deadlocked [NBC Washington]

Latino Republican Seeks Late Entry Into Arizona Senate Race [The Arizona Republic]

Nevada Democrats File Complaint Against Danny Tarkanian For Alleged Campaign Finance Errors [Las Vegas Sun]

Colorado Sen. Bennet Champions Violence Against Women Act [The Colorado Independent]

Earlier on HuffPost: